EP0440006B1 - A method and arrangement for supplying direct current to a telephone line - Google Patents

A method and arrangement for supplying direct current to a telephone line Download PDF

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Publication number
EP0440006B1
EP0440006B1 EP90850396A EP90850396A EP0440006B1 EP 0440006 B1 EP0440006 B1 EP 0440006B1 EP 90850396 A EP90850396 A EP 90850396A EP 90850396 A EP90850396 A EP 90850396A EP 0440006 B1 EP0440006 B1 EP 0440006B1
Authority
EP
European Patent Office
Prior art keywords
current
circuit
voltage
line
supply
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP90850396A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0440006A1 (en
Inventor
Bengt Gustav Löfmark
Jan Ored Hakan Oredsson
Claes Johan Anders Lindberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of EP0440006A1 publication Critical patent/EP0440006A1/en
Application granted granted Critical
Publication of EP0440006B1 publication Critical patent/EP0440006B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04M—TELEPHONIC COMMUNICATION
    • H04M19/00—Current supply arrangements for telephone systems
    • H04M19/001—Current supply source at the exchanger providing current to substations
    • H04M19/005—Feeding arrangements without the use of line transformers

Definitions

  • the present invention relates to the supply of direct current to a telephone line in a telecommunication system. More particarly, but not exclusively, the invention relates to a method and an arrangement for varying the current supply characteristic within the framework of a given pattern by programming.
  • the line circuit BIMOS Line Interface Circuit (BLIC) found described in IEEE Journal of Solid-State Circuits, Vol Sc-21, No. 2, April 1986 pages 252-258.
  • the line circuit includes a DC-loop operative to supply direct current to a corresponding telephone line.
  • the line circuit (BLIC) operates in the opposite manner to the aforesaid SLIC-circuit, since it senses line current and supplies line voltage.
  • FIG. 1 Also known to the prior art is a feedback loop for the supply of direct current in a MALC-system. This system is described in MOTOROLA, Technical Developments, Volume 7, October 1987, pages 77-79.
  • Figure 2 illustrates the circuit with which the supply characteristic illustrated in Figure 1 is obtained.
  • the parameters V F , R F and I F are programmable.
  • the primary drawback with the SLIC-circuit is that the supply characteristic cannot be programmed. Consequently, when delivering SLIC-circuits to different countries, it is necessary to produce different circuits for countries in which different requirements of current supply characteristics prevail.
  • the circuits are different, inter alia, because the resistor R3, which is connected externally, varies.
  • the object of the present invention is to provide a direct current supply circuit which detects line voltage and supplies line current, and the current supply characteristic of which is suitable for supplying direct current to the subscriber line, while enabling the current supply to be varied by programming.
  • a further object of the invention is to provide a current supply circuit having short reaction times, so that the circuit is able to react quickly to a change in line voltage, by changing the line current in a corresponding manner.
  • the desired functions of the direct current supply are obtained with the inventive method and the inventive current supply circuit.
  • the circuit includes a voltage converter for detection and level-adjustment of the line voltage, a lowpass filter which comprises a capacitor and intended to filter-off speech signals, a buffer amplifier connected to the lowpass filter, and a resistor connected to the output of said amplifier.
  • the output voltage from the buffer amplifier delivers current through the resistor to a current amplifier, which supplies the actual line current.
  • the current supply characteristic according to the present invention includes four programmable parameters.
  • the first of these parameters is the supply resistance to low line currents
  • the second is an interruption point at which current limitation occurs
  • the third is the supply resistance of the circuit at current limitation
  • the fourth is the open circuit voltage of the circuit, wherein the polarity of the idling voltage can be programmed and optionally also its size.
  • these four parameters are programmed with the aid of said programmable components. Because all changes in the current supply characteristic are effected as a shunt coupling of the capacitor included in the lowpass filter, the equivalent inductance of the current supply circuit, seen from the line side, will be constant, independently of both the current supply characteristic and the operation point.
  • the advantage afforded by the constant inductance is that the reaction time of the current supply loop will be short. A constant inductance is obtained because the amplification-bandwidth-product in the current supply circuit becomes constant when shunt coupling the capacitor.
  • the advantage afforded when the current supply characteristic can be programmed is that one and the same circuit can be manufactured for different countries in which different requirements on current supply characteristic prevail.
  • the desired current supply characteristic can then be programmed, for instance in conjunction with an operational start.
  • the inventive current supply characteristic has advantages over the characteristic in the MALC-system.
  • the inventive circuit does not generate a constant line voltage and consequently does not have infinite amplification, therewith avoiding stability problems. Instead, there is used in accordance with the invention a negative resistance wherewith a sufficiently low current supply resistance is generated for the voltage drop to be practically negligible.
  • the current supply will always have a resistive character, even with current limitation.
  • the responsiveness to tolerances in the components is smaller compared with the d.c. supply circuit of the MALC-system. This is because the inventive circuit, in a fundamental state, in which the first and the second resistive components are infinitely large, has a d.c. voltage amplification through the lowpass filter and buffer amplifier which is identical to one, whereas corresponding amplification in the realization with the transconductance amplifier is determined by the quotient between two resistances and is thus determined by the tolerances thereof.
  • Figure 1 illustrates an inventive current supply circuit
  • Figure 2 illustrates the supply characteristic of the current supply circuit
  • the output voltage U out from said more low-voltage part supplies current I dc to a current amplifier 4, via a resistor R dc , which amplifies the current I dc with a factor G i and supplies the actual line current I ab .
  • the voltage converter 3 and the current amplifier 4 in the more high-voltage part 1 are included in the aforementioned SLIC-circuit.
  • the second resistive component R B is connected between said first node P1 and the one connection of the voltage limiting element 7.
  • the other connection on the voltage limiting element is connected to the second node P2.
  • the current circuit 8 is connected between said first and said second nodes P1, P2, in order to generate said generator current I which determines the open circuit voltage E of the current supply circuit.
  • the current direction determines the polarity of the voltage.
  • Figure 2 illustrates the current supply characteristic which can be obtained with the described circuit.
  • the Figure also indicates how the characteristic can be changed with the aid of the earlier mentioned programmable components in the more low-voltage part 2 of the current supply circuit.
  • the resistive components R A , R B have resistance values which can be used in practice, so that these will also determine the circuit supply resistance.
  • the characteristic exhibits two mutually connected lines, a first line A and a second line AB.
  • the lines A, AB illustrate that the circuit has different supply resistance, depending on the line voltage U ab , by the fact that the magnitude of the supply resistance is corresponded by the slope of the lines and by the fact that the lines shown in the Figure have different slopes.
  • the circuit supply resistance also includes the supply resistance in the fundamental state, although this is ignored because it is constant.
  • the slope of the first line A denotes the circuit supply resistance for the lower current region I ab ⁇ I lim .
  • the size of the slope is corresponded by the inverted value of the supply resistance, wherein a large slope (almost vertical) will thus indicate low-ohmic supply resistance.
  • the first resistive component R A is a resistor.
  • the current supply to the telephone line ab will be more high-ohmic than in the fundamental state.
  • This resistance can be given different values, by program control.
  • the resistive component R A is a string of silicon-integrated resistances, where the desired resistance is obtained with the aid of transistors.
  • different values give different supply resistances and therewith impart different slopes to the first line A. If the first resistive component R A is low-ohmic, the supply resistance will be high-ohmic and the first line A will have a gentler or small slope, whereas if the component R A is high-ohmic, the supply resistance will be low-ohmic and the line A will have a steep or large slope.
  • the line A is almost perpendicular
  • the first resistive component R A from a negative resistance, generated with the aid of a resistor in combination with a positive or negative feedback amplifier.
  • the resistor is connected between the input and the output of the feedback amplifier.
  • Different values of the negative resistance are obtained by varying the amplifier feedback, which can also be program controlled.
  • the limit line current I lim is corresponded by a limit voltage U lim .
  • the circuit supply resistance is controlled between the open circuit voltage E and said limit voltage U lim by the first resistive component R A .
  • the current supply circuit includes a lowpass filter 5
  • the impedance consists of the earlier mentioned supply resistance R feed in series with an inductance L feed .
  • the reactive element in the lowpass filter is a capacitor C1.
  • the first resistive component R A is a linear shunt to said capacitor, whereas the second resistive component R B is a non-linear shunt to the same capacitor. Since all changes in the current supply characteristic, both linear and non-linear, are reflected by shunt-coupling of this capacitor, the equivalent inductance, seen from the line side ab, will be constant, independently of both current supply characteristic and operation point. This is achieved because the product of the amplification and bandwidth in the circuit is constant at said shunt coupling to the capacitor.
  • the impedance includes an inductance is due to the fact that the circuit between the line ab and the two first nodes P1, P2 can be considered as a gyrator which transforms current to voltage and vice versa.
  • a current in the section between the nodes P1, P2 will thus correspond to a voltage on the line ab (the generator current I determines the idling voltage E) and a voltage corresponds to a line current I ab (the voltage limiting element 7 results in current limitation on the line ab).
  • a shunt-connected resistance therewith transforms to a series resistance on the line and, in the same way, the parallel capacitance C1 is transformed to a series inductance L feed .

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Devices For Supply Of Signal Current (AREA)
  • Networks Using Active Elements (AREA)
  • Interface Circuits In Exchanges (AREA)
  • Sub-Exchange Stations And Push- Button Telephones (AREA)
  • Delivering By Means Of Belts And Rollers (AREA)
  • Folding Of Thin Sheet-Like Materials, Special Discharging Devices, And Others (AREA)
EP90850396A 1990-02-01 1990-12-05 A method and arrangement for supplying direct current to a telephone line Expired - Lifetime EP0440006B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9000366A SE465547B (sv) 1990-02-01 1990-02-01 Saett och krets foer likstroemsmatning till en telefonlinje
SE9000366 1990-02-01

Publications (2)

Publication Number Publication Date
EP0440006A1 EP0440006A1 (en) 1991-08-07
EP0440006B1 true EP0440006B1 (en) 1995-03-22

Family

ID=20378432

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90850396A Expired - Lifetime EP0440006B1 (en) 1990-02-01 1990-12-05 A method and arrangement for supplying direct current to a telephone line

Country Status (19)

Country Link
US (1) US5335272A (zh)
EP (1) EP0440006B1 (zh)
JP (1) JPH05504244A (zh)
KR (1) KR0129036B1 (zh)
CN (1) CN1026940C (zh)
AU (1) AU646836B2 (zh)
BR (1) BR9007984A (zh)
CA (1) CA2070785A1 (zh)
DE (1) DE69018057T2 (zh)
DK (1) DK0440006T3 (zh)
DZ (1) DZ1479A1 (zh)
ES (1) ES2069729T3 (zh)
FI (1) FI923024A (zh)
IE (1) IE67355B1 (zh)
NO (1) NO922726D0 (zh)
PT (1) PT96643B (zh)
SE (1) SE465547B (zh)
TN (1) TNSN91004A1 (zh)
WO (1) WO1991011876A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5801520A (en) * 1994-11-10 1998-09-01 Telefonaktiebolaget Lm Ericsson Supply voltage switching apparatus

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4139608A1 (de) * 1991-11-30 1993-06-03 Siemens Nixdorf Inf Syst Verfahren zur versorgungsspannungseinstellung der speiseeinrichtung von teilnehmeranschlussschaltungen
US5249226A (en) * 1992-03-02 1993-09-28 Advanced Micro Devices, Inc. Apparatus for controlling a current supply device
SE9400186D0 (sv) * 1994-01-21 1994-01-21 Ericsson Telefon Ab L M Förfarande i ett telekommunikationssystem
US5659610A (en) * 1994-09-28 1997-08-19 Lucent Technologies Inc. Battery feed circuit
JP2845181B2 (ja) * 1995-09-22 1999-01-13 日本電気株式会社 加入者回路
JP2760325B2 (ja) * 1995-09-22 1998-05-28 日本電気株式会社 加入者回路
US5934938A (en) * 1996-08-20 1999-08-10 Chrysler Corporation Split seal retainer for an electrical connector
US5823808A (en) * 1996-08-20 1998-10-20 Chrysler Corporation Cam lever operated connector
US5913691A (en) * 1996-08-20 1999-06-22 Chrysler Corporation Dual power/control connector
US5820409A (en) * 1996-08-20 1998-10-13 Chrysler Corporation Rotatable pin connector
US6301358B1 (en) * 1998-05-29 2001-10-09 Avaya Technology Corp. Dual-slope current battery-feed circuit
US6606383B1 (en) 1999-04-19 2003-08-12 Adtran Inc. Automatic remote termination sensing and line powering scheme
DE10140358C2 (de) 2001-08-17 2003-07-10 Infineon Technologies Ag Telefonsystem mit Stromregelung im Konstantstrombereich
DE102005020896B4 (de) * 2005-05-04 2007-12-13 Infineon Technologies Ag Verfahren und Regelschaltung zur Erzeugung einer Versorgungsgleichspannung für ein analoges Telefon

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4476350A (en) * 1981-02-17 1984-10-09 Bell Telephone Laboratories, Incorporated Battery feed circuit
SE433284B (sv) * 1982-09-17 1984-05-14 Ericsson Telefon Ab L M Anordning for strommatning av en abonnentapparat
SE433285B (sv) * 1982-09-22 1984-05-14 Ericsson Telefon Ab L M Anordning for strommatning av en abonnentapparat
US4563547A (en) * 1983-03-07 1986-01-07 At&T Bell Laboratories Loop-start/ground-start line interface circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5801520A (en) * 1994-11-10 1998-09-01 Telefonaktiebolaget Lm Ericsson Supply voltage switching apparatus

Also Published As

Publication number Publication date
SE9000366L (sv) 1991-08-02
SE9000366D0 (sv) 1990-02-01
CN1026940C (zh) 1994-12-07
AU7146791A (en) 1991-08-21
CN1053873A (zh) 1991-08-14
DZ1479A1 (fr) 2004-09-13
TNSN91004A1 (fr) 1992-10-25
KR920704488A (ko) 1992-12-19
WO1991011876A1 (en) 1991-08-08
DK0440006T3 (da) 1995-07-31
FI923024A0 (fi) 1992-06-29
NO922726L (no) 1992-07-10
AU646836B2 (en) 1994-03-10
SE465547B (sv) 1991-09-23
BR9007984A (pt) 1992-10-27
IE67355B1 (en) 1996-03-20
PT96643A (pt) 1992-10-30
CA2070785A1 (en) 1991-08-02
KR0129036B1 (ko) 1998-04-08
DE69018057T2 (de) 1995-07-27
ES2069729T3 (es) 1995-05-16
DE69018057D1 (de) 1995-04-27
PT96643B (pt) 1998-08-31
FI923024A (fi) 1992-06-29
NO922726D0 (no) 1992-07-10
JPH05504244A (ja) 1993-07-01
IE910208A1 (en) 1991-08-14
EP0440006A1 (en) 1991-08-07
US5335272A (en) 1994-08-02

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